Switching circuits are widely utilized in a number of power supply applications. Three basic topologies of such switching circuits include (1) a buck converter, (2) a boost converter, and (3) a buck-boost converter. However, when multiple output are required, SIMO power converters can reduce cost and size of the device because only one inductor is used.
Conventional SIMO converters typically utilize a “priority” control scheme. According to the “priority” control scheme, when a SIMO converter detects that the voltage of one output is dropping too low, the SIMO converter would cut off power delivery to other output during subsequent cycles to compensate the output with the low voltage. This control scheme can cause high-ripple in the cut-off output because of a lack of power supply during the subsequent cycles. Other SIMO power converter techniques use digital control which are complicated and expensive. Accordingly, there is a need for efficient and cost-effective control circuits for SIMO power converters.